PubMed Health⌕ Search

Biomedical subjects

M Forsman

Publications and source records attributed to M Forsman.

At least 19 recordsLinked to original sources
PubMed2006

Trapezius muscle rest time during standardised computer work--a comparison of female computer users with and without self-reported neck/shoulder complaints.

Work related musculoskeletal disorders (WMSDs) in the shoulder/neck area are a common and increasing problem among European computer workers, especially women. Long-term low-level workloads with low degree of muscle rest are a potential risk factor for developing WMSDs. The purpose of the present study of female computer users (age 45-65 years) in Denmark and Sweden was to investigate if subjects with self-reported neck/shoulder complaints (cases, N=35) show less trapezius muscle relative rest time (RRT) than controls (N=44) when performing standardised short-term computer work tasks in controlled laboratory conditions. Surface electromyography (EMG) signals were recorded bilaterally from the upper trapezius muscles during a type, edit, precision and colour word stress task. Besides RRT, 10th percentile RMS values were calculated. On the average, 15 of the cases and 18 of the controls showed analysable EMG files per task. For the colour word stress task, the results showed lower RRT values and higher 10th percentile RMS amplitude levels among cases compared to controls. No such signs could be found for the other tasks performed. The present results indicate an increased motor response to a psychological stressor among subjects with self-reported neck/shoulder complaints.

Aged↗
PubMed2005

Dupuytren's contracture; increased cellularity--proliferation, is there equality?

BACKGROUND: Dupuytren's disease is a chronic inflammatory process which causes contractures of the fingers by shortening and thickening the palmar fascia. During the proliferative phase, fibroblasts transform into myofibroblasts apparently under the influence of several different factors. The disease usually develops slowly, but in some patients it tends to develop aggressively. The pathogenesis of Dupuytren's disease remains unsolved. In this study, we analyzed some histological characteristics that seem to predict rapid recurrence. MATERIAL AND METHODS: 21 patients were divided into two groups. In 11 patients the disease was classified as aggressive because it had recurred within two years after an operation. In 10 cases it was non-aggressive, as no recurrence had been seen. Five control samples were taken from healthy palmar aponeurosis. The differences in cellularity, collagen, Ki-67, MSA, alpha-SMA and tenascin between the specimens were analyzed using immunohistochemistry. RESULTS: Alpha-SMA and Ki-67 were present more often in the aggressive specimens. Immunohistochemical stainings for macrophages and lymphocytes were negative. CONCLUSION: There may be differences in the histology and/or immunohistochemical appearance of pathological palmar connective tissue cords in aggressive and normal Dupuytren's disease. Further studies are needed to elucidate the pathogenesis of this disease.

Adult↗
PubMed2002

A method for evaluation of manual work using synchronised video recordings and physiological measurements.

Industrial interventions that focus on increased productivity may impair the ergonomics, on a workstation or individual level. This paper presents a method that characterises work time consumption and physical work load of manual work, using video recordings synchronised with physiological measurements of, e.g. muscular activity, and postures. The underlying idea was that it is possible to amalgamate technical and human aspects resulting in a synergetic evaluation. The method was developed through two case studies within the Swedish automotive industry, where manual materials handling was studied. A methodological result was that the synchronising procedure was sufficiently precise to allow work activities to be assigned significantly different levels of physical work load. These different levels may be used to predict physical work load in the design and change of production systems. It was concluded that the method is accurate enough to be a useful tool in industrial interventions.

Automobiles↗
PubMed2001

[Anthrax--the Swedish perspective].

The recent occurrence in the USA of deliberate release of virulent Bacillus anthracis in letters sent to three media corporations and to the American senate has led to a great anxiety in Sweden and elsewhere in Europe. Numerous letters have been suspected to contain B. anthracis spores and several have contained powder of different types. In none of the tested letters collected by the Swedish police have we been able to detect anthrax bacilli. Powder containing letters have been tested with either bacterial isolation and/or B. anthracis specific PCR. Anthrax is a disease found naturally in herbivores and is occasionally spread to humans. It is caused by the gram-positive rod B. anthracis that was discovered by Robert Koch in 1876. Beginning in the 1930s many states have developed B. anthracis for use as a weapon. A few releases of the bacteria have been reported before October 2001. B. anthracis causes three forms of disease, cutaneous, pulmonary and gastro-intestinal. The pulmonary form is the most dangerous and may lead to death merely one to two days after onset of severe symptoms. This is due to the rapid growth and release of several potent toxins that engage the immune system and promote tissue destruction. B. anthracis infection can be treated with several antibiotics, among which quinolones and tetracyclins have been recommended. Diagnosis can readily be achieved by microscopy, bacterial isolation and PCR at the Swedish Institute for Infectious Disease Control and the Swedish Defence Research Agency. Antibiotics relevant for treatment of B. anthracis infections are already stockpilled in our country. Further actions to strengthen our capability to deal with bioterrorism are ongoing.

Anthrax↗
PubMed2001

Biomonitoring of continuous microbial community adaptation towards more efficient phenol-degradation in a fed-batch bioreactor.

The anaerobic degradation of phenol was studied in a fed-batch culture. Nitrate was added as electron acceptor and phenol was provided three times, to a final concentration of 200 mg/l. Randomly amplified polymorphic DNA (RAPD) and terminal fraction fragment length polymorphism (T-RFLP) were used and compared in order to monitor the microbial succession in the reactor. Phenol degradation started after an initial lag phase of 14 days and was then completed within a few days. In addition, the duration of the lag phase was shortened and the degradation rate was increased after each phenol amendment. Nitrate reduction correlated with microbial growth and phenol depletion, confirming that the degradation was carried out anaerobically. Results from the DNA analysis showed that the structure of the microbial community changed after each phenol amendment. This study confirms the potential for anaerobic degradation of environmental pollutants and also confirms that microbial acclimation towards faster degradation rates occurred upon repeated substrate amendments. Furthermore, both of the DNA-based techniques described the phenol degradation-linked community shifts with similar general results. RAPD is a faster, simpler technique that gives a higher resolution and consequently reflects the shifts in the microbial community structure better, whereas T-RFLP is more suitable for phylogenetic studies.

Adaptation, Physiological↗
PubMed2001

Identification and analysis of unsatisfactory psychosocial work situations: a participatory approach employing video-computer interaction.

A method for psychosocial evaluation of potentially stressful or unsatisfactory situations in manual work was developed. It focuses on subjective responses regarding specific situations and is based on interactive worker assessment when viewing video recordings of oneself. The worker is first video-recorded during work. The video is then displayed on the computer terminal, and the filmed worker clicks on virtual controls on the screen whenever an unsatisfactory psychosocial situation appears; a window of questions regarding psychological demands, mental strain and job control is then opened. A library with pictorial information and comments on the selected situations is formed in the computer. The evaluation system, called PSIDAR, was applied in two case studies, one of manual materials handling in an automotive workshop and one of a group of workers producing and testing instrument panels. The findings indicate that PSIDAR can provide data that are useful in a participatory ergonomic process of change.

Computers↗
PubMed2001

Motor unit recruitment in the trapezius muscle with special reference to coarse arm movements.

Chronic shoulder pain is common in a variety of occupations. The "Cinderella hypothesis" suggests that the pain originates from damaged type I muscle fibres driven into degenerative processes as a result of too long activation and too short recovery time. The main purpose of this study was to investigate if the same motor units are active during all phases of coarse arm movements. Eight healthy volunteers participated in the study. Intramuscular electromyographic signals were picked up with a four-lead fine wire electrode, during a unilateral straight arm movement. The movement started with either (part 1) an abduction or a flexion, then (2) a movement in the horizontal plane from the sagittal to the frontal plane or vice versa, and finally (3) an adduction or an extension to the start position. The movement cycle was performed in three different speeds, slow, medium, and high, with one, two or five cycles per 20 s, respectively. On an average, the motor unit action potentials (MUAPs) of 6 motor units (range, 1-15) were identified per trail. In total 94% of the MUAP trains that were identified showed firings in all 3 parts of the movements. The findings support the Cinderella hypothesis, although there is a need to further investigate the temporal pattern of long-term motor unit activity.

Action Potentials↗
PubMed2001

Phenotypic biomonitoring using multivariate flow cytometric analysis of multi-stained microorganisms.

A new method for monitoring phenotypic profiles of pure cultures and complex microbial communities was evaluated. The approach was to stain microorganisms with a battery of fluorescent dyes prior to flow cytometry analysis (FCM) and to analyse the data using multivariate methods, including principal component analysis and partial least squares. The FCM method was quantitatively evaluated using different mixtures of pure cultures as well as microbial communities. The results showed that the method could quantitatively and reproducibly resolve both populations and communities of microorganisms with 5% abundance in a diverse microbial background. The feasibility of monitoring complex microbial communities over time during the biodegradation of naphthalene using the FCM method was demonstrated. The biodegradation of naphthalene occurred to differing extents in microcosms representing three different types of aromatic-contaminated groundwater and a sample of bio-basin water. The FCM method distinguished each of these four microbial communities. The phenotypic profiles were compared with genotypic profiles generated by random-amplified polymorphic DNA analysis. The genotypic profiles of the microbial communities described only the microbial composition, and not their functional change, whereas the phenotypic profiles seemed to contain information on both the composition and the functional change of the microorganisms. Furthermore, event analysis of the FCM data showed that microbial communities with initially differing compositions could converge towards a similar composition if they had a capacity for high levels of degradation, whereas microbial communities with similar initial compositions could diverge if they differed in biodegrading ability.

Journal Article↗
PubMed2001

Role of the DmpR-mediated regulatory circuit in bacterial biodegradation properties in methylphenol-amended soils.

Pathway substrates and some structural analogues directly activate the regulatory protein DmpR to promote transcription of the dmp operon genes encoding the (methyl)phenol degradative pathway of Pseudomonas sp. strain CF600. While a wide range of phenols can activate DmpR, the location and nature of substituents on the basic phenolic ring can limit the level of activation and thus utilization of some compounds as assessed by growth on plates. Here we address the role of the aromatic effector response of DmpR in determining degradative properties in two soil matrices that provide different nutritional conditions. Using the wild-type system and an isogenic counterpart containing a DmpR mutant with enhanced ability to respond to para-substituted phenols, we demonstrate (i) that the enhanced in vitro biodegradative capacity of the regulator mutant strain is manifested in the two different soil types and (ii) that exposure of the wild-type strain to 4-methylphenol-contaminated soil led to rapid selection of a subpopulation exhibiting enhanced capacities to degrade the compound. Genetic and functional analyses of 10 of these derivatives demonstrated that all harbored a single mutation in the sensory domain of DmpR that mediated the phenotype in each case. These findings establish a dominating role for the aromatic effector response of DmpR in determining degradation properties. Moreover, the results indicate that the ability to rapidly adapt regulator properties to different profiles of polluting compounds may underlie the evolutionary success of DmpR-like regulators in controlling aromatic catabolic pathways.

Bacterial Proteins↗
PubMed2000

Francisella tularensis does not manifest virulence in viable but non-culturable state.

Francisella tularensis is a small Gram-negative bacterium that causes tularemia in animals and man. The disease can be transmitted by handling of infected animals, by contaminated dust, by insect vectors, or by drinking contaminated water. In the present study cells of F. tularensis were subjected to extended storage in cold water devoid of carbon sources. Total cell counts remained constant throughout a 70-day period and beyond, while plate counts decreased to an undetectable level after 70 days. Attempts to resuscitate the cells were unsuccessful. Quantitative PCR targeting the 16S rDNA of F. tularensis showed an increase in variability after 25 days and the signal was lost after 45 days. Metabolic activity, measured by accumulation of rhodamine 123, declined to approximately 35% after a 140-day period. Analyses of substrate responsiveness of cells stored for 140 days in cold water showed that approximately 30% of the population increased in size after incubation in rich medium in the presence of nalidixic acid. Approximately 10(5) of these cells were injected intraperitoneally into mice. No signs or symptoms of tularemia were observed during 3 weeks. In addition, there was no evidence of stimulation of lymphocytes with F. tularensis as recall antigen. In conclusion, viable but non-culturable cells of F. tularensis are avirulent in mice, giving new insight into the ecological niche of this bacterium.

Journal Article↗
PubMed2000

Intragastric movement assessment by measuring magnetic field decay of magnetised tracer particles in a solid meal.

The aim of the study is to evaluate and further develop a non-invasive method for the measurement of intragastric movements. Ferrimagnetic particles (gamma-Fe2O3) are ingested within a standard test meal (pancakes), and given a permanent magnetisation by an applied homogeneous magnetic field. Magnetic measurements are performed outside the stomach, using fluxgate magnetometers anterior and posterior, in seven periods of 12 minutes each. Any movements caused by grinding and mixing in the ingesta would result in a misalignment of the magnetic moments, and hence in a decay of the external magnetic field. Twelve healthy male volunteers, aged 26.7 +/- 2.7 years (mean +/- SD), are studied. After an initial phase of low and almost linear flux density decay (32 +/- 19%, from minute 10 to minute 22 postprandially), the mean rotation and decay gradually increases (67 +/- 21%, from minute 100 to 112), and the decay becomes bi-exponential. It is hypothesised that the bi-exponential nature of the decay corresponds to the relative fractions, solid and semifluid, of gastric content. The decay curves often show superimposed 3 cycles min-1 variations, which correlate well with the basic electrical rhythm of the stomach measured by electrogastrography (EGG). It is concluded that these variations are induced by gastric contractions.

Adult↗
PubMed2000

Intramuscular pressure of the infra- and supraspinatus muscles in relation to hand load and arm posture.

In work engaging the upper extremities, the musculoskeletal system of the shoulder is sometimes exposed to prolonged excessive load, leading to musculoskeletal disorders of the shoulder. One way of reducing work-related shoulder disorders is to establish guidelines for working postures. The purpose of this study was to identify harmful working positions, by performing a comprehensive survey of the intramuscular pressure (IMP) in the infra- and supraspinatus muscles in relation to different arm positions and external loads. Ten healthy males participated, and the IMP in the infra- and supraspinatus muscles was studied in a total of 112 combinations of arm positions and hand loads at levels that occur frequently in industrial work. High-precision spatial recordings were accomplished with a three-dimensional motion-analysis system, and the IMP was measured using the microcapillary infusion technique. The mean IMP of the infraspinatus muscle as well as that of the supraspinatus muscle increased continuously from a resting pressure at 0 degrees of upper arm elevation to a maximal pressure at 90 degrees of upper arm elevation, for all elevation planes. The mean IMP of the supraspinatus muscle appeared to be more dependent upon the elevation plane and less dependent upon the hand load, compared to the infraspinatus muscle. Even during only moderate arm elevation, the mean IMP of the infra- and supraspinatus muscles, presented here in polar diagrams, had already exceeded the levels of reduced recovery from local muscle fatigue and blood flow impairment. The elevation angle and the hand load primarily influence the development of IMP in the infra- and supraspinatus muscles.

Adult↗
PubMed2000

Influence of TNT transformation on microbial community structure in four different lake microcosms.

After World War II, large amounts of obsolete ammunition were dumped in various lakes in Sweden. Trinitrotoluene, TNT, was one of the main components of the dumped explosives. In this study, four different lake microcosms originating from lakes where relatively large amounts of ammunition were dumped were used to mimic the effect of TNT release on the natural microbial community. Increased microbial growth was found in lake microcosms amended with TNT. However, negligible mineralization of TNT was detected, suggesting that TNT was not utilized as a carbon source, but as a nitrogen source. Random amplified polymorphic DNA (RAPD) analysis indicated that the TNT induced no significant differences in microbial community composition and therefore, no major changes in natural selection, despite the increased microbial growth in the presence of the compound. More than 95% of the added TNT bound irreversibly to the sediments, possibly as a result of microbial transformation to reactive metabolites that subsequently bound covalently to components of the sediment. The results, taken together, suggest that no permanent change in the microbial ecology occurred as a result of the TNT amendment. This was probably due partly to the transient exposure of the microbial communities to the TNT before it became irreversibly bound to the sediment, and partly to the fact that TNT was not a primary growth substrate that strongly affects natural selection.

Bacteria↗
PubMed2000

Comparative analysis of PCR versus culture for diagnosis of ulceroglandular tularemia.

PCR and culture were comparatively evaluated for their abilities to demonstrate Francisella tularensis in wound specimens from tularemia patients during an outbreak in Sweden in 1998. For transport of the specimens used for PCR, a buffer solution containing a nuclease inhibitor was used, and for transport of the specimens used for culture, a commercial transport system was selected after experimental comparison of various systems. Of 40 patients with culture- and/or serology-verified ulceroglandular tularemia, PCR detected F. tularensis DNA in 30 (75%) patients, whereas culture detected bacterial growth in 25 (62%) patients. Compared to data from a previous study, the present inclusion of a nuclease inhibitor in the transport medium did not improve the sensitivity of the PCR, whereas the sensitivity of the culture procedure was significantly increased by selection of the system used for transport. Among eight patients with clinically suspected tularemia but with negative serology and culture, specimens from four patients showed detectable DNA. In three of these patients the diagnosis was verified by the demonstration of an F. tularensis-specific T-cell response in vitro. In conclusion, PCR was more sensitive than culture for demonstration of F. tularensis in wound specimens. Besides, we showed that tularemia may proceed without development of serum antibodies, and in these patients, PCR may be of special importance for verification of the diagnosis.

Adult↗
PubMed1999

Paraplegia after thoracotomy--not caused by the epidural catheter.

BACKGROUND: Paraplegia and peripheral nerve injuries may arise after general anaesthesia from many causes but are easily ascribed to central block if the latter has been used. CASE REPORT: A 56-yr-old woman, with Bechterev disease but otherwise healthy, was operated with left-sided thoracotomy to remove a tumour in the left lower lobe. She had an epidural catheter inserted in the mid-thoracic area before general anaesthesia was started. Bupivacaine 0.5% 5 ml was injected once and the infusion of bupivacaine 0.1% with 2 micrograms/ml fentanyl and 2 micrograms/ml adrenaline (5 ml/h) started at the end of surgery. The patient woke up with total paralysis in the lower limb and sensory analgesia at the level of T8, which remained unchanged at several observations. Laminectomy, performed 17 h after the primary operation, showed a large piece of a haemostatic sponge (Surgicel) compressing the spinal cord, which was then decompressed but the motor and sensory deficit remained virtually unchanged both then and a year later. CONCLUSIONS: This case shows--once again--that although central blocks may cause serious neurological complications and paraplegia, other causes are possible and have to be considered. However, all patients with an epidural catheter must be monitored for early signs and symptoms of an intraspinal process and the appropriate treatment has to be instituted instantly.

Anesthesia, Epidural↗
PubMed1999

Recruitment of low threshold motor-units in the trapezius muscle in different static arm positions.

A prevailing hypothesis for development of myalgia symptoms in the trapezius muscle is based on observations that in stereotypic activation of muscle the same low-threshold motor-units are the first ones to be recruited, and that these units are active throughout the contraction, until total relaxation. The theory suggests that these units are the first ones in monotonous repetitive work to be subject to degenerative processes, causing pain. The present project was undertaken to evaluate to what extent recruitment of motor-units in the trapezius muscle is position-specific, i.e. if there are motor-units that are recruited over a wide range of arm postures. Fine wire electrode pairs, inserted 2 cm lateral to the midpoint between the acromion and the C7 spinous processus, were used for signal acquisition. Methods for decomposition of the interference patterns were developed, allowing identification of single motor-units in signals registered in different arm positions. Voluntary recruitment of motor-units in the descending portion of the trapezius muscle was studied in 24 different arm positions (0-90 degrees shoulder flexion, 0-45 degrees humeral abduction, and 45-135 degrees elbow flexion) in three subjects. The results showed that the wire electrode technique and the signal processing algorithm employed allowed motor-unit identification in non-isometric conditions. It was found that low threshold motor-units in the trapezius muscle, active over a wide range of arm positions, could be identified in all three subjects. We refer to those as Cinderella, or C, units. These results support the research hypothesis addressed.

Adult↗